Dyslexia: Earlier identification for quicker intervention

In the UK, approximately 10% of the population is estimated to have dyslexia, with varying degrees of severity, making it the most common of learning difficulties. For school-age children, dyslexia diagnoses are conducted by qualified professionals such as specialist assessors and educational psychologists following strict guidelines provided by bodies such as the SpLD Assessment Standards Committee (SASC). 

However, discrepancies in assessment models have long resulted in variability for diagnoses, with a much-cited 2019 report indicating that British schools may be failing to identify up to 80% of dyslexic students. In the years since, there has been a greater focus on getting these numbers to align – and getting children and adolescents the support they require in their most formative years.

Historically, dyslexia was often diagnosed using the discrepancy model, which relied heavily on comparing a child's IQ with their reading abilities. This model sometimes led to delayed diagnoses, as dyslexic students could compensate for phonological weaknesses by memorising words or relying on extensive oral vocabularies. Additionally, IQ scores could play a disproportionate role, with students often missing out on diagnoses if their scores didn't meet certain thresholds.

Phonological awareness, which refers to the recognition and manipulation of language sounds, has emerged as a crucial aspect in dyslexia diagnosis. Unlike the discrepancy model, modern assessments prioritise evaluating phonological skills, recognising their central role in dyslexia. Tasks such as phoneme segmentation, blending, deletion, and manipulation provide invaluable insights into individuals' phonological processing abilities.

Contemporary assessments also consider linguistic factors like rapid automatised naming (RAN) and orthographic processing, which contribute to reading fluency and accuracy. This shift towards a more comprehensive assessment of dyslexia, focusing on phonological awareness and other cognitive processes, facilitates earlier and more accurate identification of individuals with dyslexia.

Using a comprehensive diagnostic

The Tests of Dyslexia (TOD), a comprehensive assessment tool incorporating many of these tasks, is designed to identify dyslexia and related learning difficulties in individuals aged 5 to 89 years. The TOD provides three sets of direct assessments: the TOD-Screener (TOD-S), the TOD-Early (TOD-E), and the TOD-Comprehensive (TOD-C), measuring skills across reading and spelling, linguistic processing, and vocabulary and reasoning domains. These tests can be uniquely tailored to evaluate and create a profile of individuals' reading, spelling, and linguistic abilities, aiding in the identification of dyslexia. 

The TOD assessment battery includes subtests targeting key areas such as phonological processing, rapid naming, working memory, and reading skills. The TOD-C, the most comprehensive assessment, yields a Dyslexia Diagnostic Index (DDI) which indicates the probability of an individual having dyslexia. 

Moreover, the TOD incorporates measures of nonverbal cognitive abilities to assess the cognitive profile of individuals with dyslexia comprehensively. This holistic approach ensures that the assessment captures the full range of cognitive and linguistic factors contributing to dyslexia.

With its standardised measures and clear interpretive guidelines, the TOD enables reliable and valid assessment of dyslexia, facilitating early identification and effective intervention. 

Assessing the ‘whole child’

Of course, a ‘whole-child’ assessment approach such as that of the Intelligence and Development Scales – 2^nd Edition (IDS-2) can also be useful to identify barriers to learning. 

While the IDS-2 includes many subtests that specialist assessors will recognise as being crucial in identifying markers of dyslexia (e.g. slow phonological processing, slow reading fluency and poor working memory), it also provides further insight by evaluating six domains of general development, including executive functions, psychomotor and social-emotional skills for children and young people aged 5–21 years. 

For more on the IDS-2, the TOD, or any of our other educational assessments please contact us at customersupport@hogrefe.co.uk or visit our website.